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Mineralogical, chemical and stable C and O isotope characteristics of surficial carbonate structures from the Mediterranean offshore Israel indicate microbial and thermogenic methane origin Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-02-26 Baruch Spiro, Oded Ezra, Jens Najorka, Antonio Delgado, Or Bialik, Zvi Ben-Avraham, Dwight Coleman, Yizhaq Makovsky
The Eastern Mediterranean continental slope offshore Israel became a focus of exploration for, and production of, natural gas in recent years. The 2010–2011 Nautilus ROV expedition performed detailed video recordings and sampling in two areas offshore Israel: the Palmachim disturbance, southwest of Tel Aviv, and an area offshore Acre, north of Haifa. An analytical programme regarding the carbonate
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Morphology and potential geohazards using seismo-acoustic data in Sakarya Canyon, Western Black Sea Margin Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-02-25 Aslıhan Nasıf, Derman Dondurur
Multi-channel seismic, 3.5-kHz Chirp seismic, and multibeam bathymetric data were collected along the western Black Sea margin, offshore Sakarya River, to investigate the morphology and to evaluate the potential geologic hazards. The multibeam bathymetric data show that the morphology of the margin is controlled by the Sakarya Canyon consisting of three distinct canyon heads, all incising the southern
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The Breede River estuary (Cape Province, South Africa): A historical perspective on hydrology, geomorphology, and sedimentology Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-02-25 Burg Flemming, Keith Martin
A hitherto unpublished historical dataset of the Breede River estuary, Western Cape, South Africa, that was collected in the summer season of 1983 is presented. Bathymetric, physiographic, and sedimentological data were collected at 1–1.5-km intervals between the mouth and the Malgas ferry crossing at km 35. The remaining estuary up to km 52 was not surveyed. Sedimentologically, the estuary could be
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Controls on the evolution of submarine canyons in steep continental slopes: geomorphological insights from Palar Basin, southeastern margin of India Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-02-08 S. Susanth, P. John Kurian, C. M. Bijesh, D. Twinkle, Abhishek Tyagi, S. Rajan
Palar Basin in India’s southeastern margin is an intracratonic rift basin characterized by a very steep continental slope (gradient, 3°–78°). Recently acquired high-resolution swath bathymetry data from the region documented various geomorphic features on the slope of the Palar Basin, and canyons are most prominent among them. Twenty submarine canyons, grouped as the Palar Canyon System (PCS), have
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Field observation of the wave-induced pore pressure response in a silty soil seabed Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-02-04 Xingbei Xu, Guohui Xu, Junjie Yang, Zhongqian Xu, Yupeng Ren
Liquefaction of seabed sediments under the action of storm waves is an important form of seabed instability, which may cause damage to submarine structures such as pipelines and cables. A commonly used parameter to identify sediment liquefaction is pore pressure. The pressure response of the pore water at different depths of a silty soil seabed under storm waves was monitored by a probe rod in the
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A sea bottom classification of the Robredo area in the Northern San Jorge Gulf (Argentina) Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-02-02 N. Sánchez-Carnero, D. Rodríguez-Pérez
Benthic habitats are primarily determined by the nature of the substrate (i.e., the type of sediment or rock) and by the bathymetry (e.g., light availability, current, or waves exposition) both determining the viability of infaunal organisms. In this sense multibeam (MB) echosounders provide more data about the sea bottom than any other acoustic technique. During the 2014 Argentine-Canadian survey
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Correction to: Seismic geomorphology of Cenozoic slope deposits and deltaic clinoforms in the Great South Basin (GSB) offshore New Zealand Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-15 Kamaldeen Olakunle Omosanya, Dicky Harishidayat
A Correction to this paper has been published: https://doi.org/10.1007/s00367-020-00678-0
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The influence of inhomogeneous hydrate formation on permeability anisotropy of porous media Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-13 Cong Hu, Yonggang Jia, Zhibo Duan
Hydrate formation is an inhomogeneous process, which results in permeability anisotropy, i.e., permeability differs in different directions. Permeability anisotropy of hydrate-bearing sands is analyzed based on CT (computed tomography) scanning and pore network modeling in this study. A digital sample is divided into eight different parts based on hydrate distribution. Eight equivalent micropore structures
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Seismic stratigraphy of the Klints Bank east of Gotland (Baltic Sea): a giant drumlin sealing thermogenic hydrocarbons Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-12 Wiebke Schäfer, Christian Hübscher, Daniel Sopher
This work analyses six high-resolution multi-channel seismic profiles across the Klints Bank east of Gotland. The Klints Bank consists of a drop-shaped increase of the Quaternary thickness and is oriented in an approximately north-southern direction with a length of over 50 km, a width of about 15 km and a maximum thickness of 150 m. The glacial origin of the Klints Bank can be verified with the dataset
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Using end-member analysis to determine sediment dispersal and depositional processes on the Heuksan mud belt, southwest Korean shelf Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-07 Hun Jun Ha, Tae Soo Chang, Ho Kyung Ha
Due to the large volume of the Heuksan mud belt (HMB), the source of the mud and the depositional processes involved have been controversially discussed over the past two decades. To illuminate the issue, an end-member analysis (EMA) was applied to the grain-size data of 74 surficial samples in order to determine the sediment dispersal pattern on the HMB. In addition, a sedimentary facies analysis
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Continental shelf morphology controlled by bottom currents, mud diapirism, and submarine slumping to the east of the Gaoping Canyon, off SW Taiwan Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-07 Yi-Ching Yeh, Chung-Lin Tsai, Shu-Kun Hsu, Hsiao-Shan Lin, Kuan-Ting Chen, Yen-Yu Cho, Chin-Wei Liang
The Gaoping River-Gaoping Submarine Canyon (GPC) is one of the dispersal river systems in the world. Tens of tons of terrestrial sediments discharge per year at the mouth of the river, where gravity-driven flow can damage the telecommunication cable along the 260-km-long GPC; to the east of the GPC, the continental shelf has been eroded. To understand this geological phenomenon, high-resolution sparker
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Carbon stable isotope ratio as a revealer of incomplete decarbonation for particulate organic carbon measurement in river plumes Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-07 Thierry Blasco, Christophe Migon, Guillaume Morin, Aurélie Dufour, Nathalie Vigier, Sabine Marty, David Doxaran
The characterization of particles in suspension in river plumes contributes to the assessment of net particulate organic carbon (POC) fluxes and to a better understanding of the anthropogenic and climatic impact on blue carbon. Prior to POC analysis in natural waters, inorganic carbon (in the form of carbonates) must be removed. This step is generally carried out by acid leaching. However, the presence
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Biotic response of benthic foraminifera to OMZ variations in the northwestern Pacific since the last deglaciation Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-07 Keisuke Sakai, Ken’ichi Ohkushi, Akihiko Shibahara
Recent declines in oxygen concentrations in the global oceans have been particularly acute in oxygen minimum zones (OMZ) at intermediate depths. Fossil benthic foraminifera have the potential to provide useful information on the long-term biotic responses of marine organisms to past variations in the OMZ. During the last deglaciation, the OMZ at 1 km water depth in the northwestern Pacific Ocean intensified
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Quantifying clay mineral sources in marine sediments by using end-member mixing analysis Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-07 Tao Li, Guanqiang Cai, Chaowen Wang, Kai Liang, Shengzhong Ma, Weidong Luo
This study applied end-member mixing analysis (EMMA) to clay minerals in Taiwan Strait sediments to determine the proportional contributions from known riverine sources, which are called end-members. Three end-members were thus determined: the rivers of Taiwan (TW), the rivers of Zhu and Min (ZM), and the rivers of Luzon (LZ). The EMMA model yielded strong and unbiased estimates of the clay mineral
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Crustal structure and Moho topography of the southern part (18° S–25° S) of Central Indian Ridge using high-resolution EIGEN6C4 global gravity model data Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-06 Soumyashree Debasis Sahoo, Sanjit Kumar Pal
The sophisticated tectonic setting and obscure structural heterogeneity over the Central Indian Ridge (CIR) make it a challenging target for geophysical study. The present study deals with the mapping of crustal structure over the southern part (18° S–25° S) of the CIR using EIGEN6C4 Bouguer gravity data. We have used the Radial Average Power Spectrum (RAPS) technique to estimate Moho depths and compared
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Salinity effects on cultured Neogloboquadrina pachyderma (sinistral) from high latitudes: new paleoenvironmental insights Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-05 Jacqueline Bertlich, Nikolaus Gussone, Jasper Berndt, Heinrich F. Arlinghaus, Gerhard S. Dieckmann
This study presents culture experiments of the cold water species Neogloboquadrina pachyderma (sinistral) and provides new insights into the incorporation of elements in foraminiferal calcite of common and newly established proxies for paleoenvironmental applications (shell Mg/Ca, Sr/Ca and Na/Ca). Specimens were collected from sea ice during the austral winter in the Antarctic Weddell Sea and subsequently
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Slope instability detection for muddy submarine channels using sub-bottom profile images based on bidimensional empirical mode decomposition Geo-Mar. Lett. (IF 1.429) Pub Date : 2021-01-03 Cunyong Zhang
Slope stability is a key problem for safe submarine channel operation on muddy coasts. The early detection and identification of slope instabilities is important to allow safety measures to be taken in a timely manner. Owing to the difficulties in predicting or providing early forecasts of slope collapse in muddy submarine channels, this study introduces a bidimensional empirical mode decomposition
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Constraints of salinity- and sediment-induced stratification on the turbidity maximum in a tidal estuary Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-09-08 Ting Lu; Hao Wu; Fan Zhang; Jiasheng Li; Liang Zhou; Jianjun Jia; Zhanhai Li; Ya Ping Wang
The vertical density gradients of salinity and suspended sediment concentration (SSC) cause stratification in estuaries, which play a vital role in the turbulence structure, water mixing, and sediment transport. To investigate the effect of stratification, especially SSC-induced stratification, on maintaining the estuarine turbidity maximum (ETM), we conducted in situ measurements on sediment dynamics
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Oceanic sediment accumulation rates predicted via machine learning algorithm: towards sediment characterization on a global scale Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-08-29 Giancarlo A. Restreppo; Warren T. Wood; Benjamin J. Phrampus
Observed vertical sediment accumulation rates (n = 1031) were gathered from ~ 55 years of peer reviewed literature. Original methods of rate calculation include long-term isotope geochronology (14C, 210Pb, and 137Cs), pollen analysis, horizon markers, and box coring. These observations are used to create a database of global, contemporary vertical sediment accumulation rates. Rates were converted to
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Active deformation of Sagami Bay triggered by approach of the Izu island arc Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-08-12 Ayanori Misawa; Juichiro Ashi; Kenji Tara; Mikiya Yamashita; Masataka Kinoshita
Sagami Bay in central Japan is known as the seismogenic and tsunamigenic zone of the 1703 and 1923 Kanto earthquakes that caused devastating damage in the Tokyo metropolitan area. However, the tsunamigenic structure within the frontal wedges of the subduction zone remains unresolved after the last disastrous events. In the present study, the detailed structural features of the shallowest structure
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Interaction between seabed morphology and water mass in the South Eastern Arabian Sea: deductions of water mass flow Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-07-24 Sacchi Rajappa; John P. Kurian; Abhishek Tyagi; Nuncio Murukesh
Geomorphic analysis utilizing multibeam bathymetry and sediment profiler data along with conductivity, temperature and depth (CTD) measurements was undertaken to investigate morphological aspects of bottom current features that prevail in the area. The aim of the study was to deduce the prevailing water mass in the area and to infer interactions between water mass and seabed of South Eastern Arabian
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Aeration-induced marine sediment acidification in the vicinity of Rizhao Port, western Yellow Sea Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-07-06 Ya-Chao Qin
Two short-term summer cruises were performed in the vicinity of Rizhao Port, western Yellow Sea, to investigate summer water stratification and the phenomenon of marine sediment acidification. Results show that water stratification has formed as early as in May. The chemoclines of dissolved oxygen (DO) and pH usually occur deeper than the thermocline. Sometimes the chemoclines of DO and pH occur synchronously
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Terraces, reefs, and valleys along the Brazil northeast outer shelf: deglacial sea-level archives? Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-07-02 Moab Praxedes Gomes; Helenice Vital; André Willy Droxler
Morphological features on low-latitude continental shelves have recorded past sea level fluctuations. This study aims to recognize and interrogate, on the Rio Grande do Norte (RN, NE Brazil) outer shelves, specific seabed morphologies that could have been produced by the punctuated relative sea level rise of the last deglaciation. These sea floor morphologies, imaged by single-beam bathymetric data
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Assessing the efficacy of nourishment of a Mediterranean beach using bimodal fluvial sediments and a specific placement design Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-06-20 Matteo Vacchi; Giorgio Berriolo; Chiara F. Schiaffino; Alessio Rovere; Edward A. Anthony; Nicola Corradi; Marco Firpo; Marco Ferrari
Several studies have highlighted the difficulties inherent to the use of bimodal fluvial sediments in beach nourishment and the resulting unpredictable behaviour of the beach profile. In this paper, we monitored the temporal evolution of a nourishment project carried out on a northwestern Mediterranean beach and using fluvial mixed sand and gravel nourishment material. The main aim of the study was
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3D modelling of beach topography changes caused by the tombolo phenomenon using terrestrial laser scanning (TLS) and unmanned aerial vehicle (UAV) photogrammetry on the example of the city of Sopot Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-06-17 Cezary Specht; Pawel S. Dabrowski; Mariusz Specht
In 2011, a yacht marina was built in Sopot (the largest holiday resort in Poland), which initiated the formation of a local shallowing of the bottom related to the tombolo effect. The building of the marina led to disturbances in the transmission of bottom deposits along the coast, which resulted from waves and the shift of the beach coastline by approx. 50 m towards the sea. Its effects include progressive
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Retraction Note to: Late Quaternary stable isotope record and meltwater discharge anomaly events to the south of the Antarctic Polar Front, Drake Passage Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-06-09 Sung Ho Bae, Ho Il Yoon, Byong-Kwon Park, Yeadong Kim
This article [1] has been retracted at the request of the Editors-in-Chief because it has been previously published by Bae, S.H., Yoon, H.I., Park, B. et al [2]. This article is therefore redundant.
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Morphometric scaling of subsurface vent complexes: implications for a new classification scheme Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-06-05 Shambel B. Mituku; Kamaldeen Olakunle Omosanya
This paper provides a novel classification scheme for magma-induced subsurface vent complexes based on morphometric data and stacking patterns. The study area is the Naglfar Dome in the Vøring Basin where the interaction between magmatic intrusions and vent complexes is well known. Seismic interpretation, characterization and morphometric analyses of 35 vent complexes observed within the Palaeocene-Eocene
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Assessing the effects of shoreface profile concavity on long-term shoreline changes: an exploratory study Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-06-01 Junjie Deng; Jiaxue Wu
Coastal erosion under the context of global sea-level rise has threatened societies living along the coast. The processes related to decadal- to centennial-scale shoreline changes are much more complex than those suggested by the Bruun effect. This paper derives a one-dimensional model to explore the relationships between shoreline change, profile concavity, and sediment fluxes in wave-dominated coastal
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Quaternary warming and cooling trends in the Bransfield Basin, Antarctic Peninsula, based on gamma-ray spectrometry Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-05-24 Jeniffer Alves Nobre; Antonio Fernando Menezes Freire; Arthur Ayres Neto; Mateus dos Santos Martins; Cleverson Guizan Silva; Rosemary Vieira
Spectral gamma-ray measurements were carried out on eight cores collected in the Bransfield Strait at points distributed over a cross section connecting the South Shetland Islands (NW) and the Antarctic Peninsula (SE). These cores were acquired during the cruises OPERANTAR XXXIII, XXXIV, and XXXV, aboard the P/V Almirante Maximiano, from the Brazilian Navy, within the scope of the project “Use of Sedimentary
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Quaternary continental shelf basins of Saronikos Gulf, Aegean Sea Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-05-21 Panagiotis M. Foutrakis; George Anastasakis
The Saronikos Gulf hosts the northwestern end of the South Aegean Active Volcanic Arc. It is affected by extensional back-arc tectonism in a prominent N-S direction, while older E-W rifting is also manifested. Recently acquired swath bathymetry and high-resolution seismic profiles led to the precise morphological mapping of five Quaternary continental shelf basins, along with their neotectonic delineations
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Elevated turbidity and dissolved manganese in deep water column near 10°47’S Central Indian Ridge: studies on hydrothermal activities Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-05-16 Durbar Ray; K. A. KameshRaju; A. Srinivas Rao; L. SuryaPrakash; Abhay V. Mudholkar; V. Yatheesh; Kiranmai Samudrala; Dalayya Kota
The deep water in the ridge segment between 10°18’S and 10°57’S of northern Central Indian Ridge was surveyed with CTD and AUV for seafloor hydrothermal activities. During the survey, 25 CTD hydrocasts were made, and seawater samples were collected for analyses of chemical tracers like dissolved manganese (DMn). In the rift valley between 10°40’S and 10°57’S, consistent backscatter anomalies (up to
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Methane seeps on the outer shelf of the Laptev Sea: characteristic features, structural control, and benthic fauna Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-05-15 B. Baranov; S. Galkin; A. Vedenin; K. Dozorova; A. Gebruk; M. Flint
Two areas with cold methane seeps on the outer shelf of the Laptev Sea were studied by two interdisciplinary expeditions onboard the RV Akademik Mstislav Keldysh in August–September of 2017 and 2018. These fields lie in water between depths of 63 and 73 m, and in a region of growing interest to the international community. Characteristic features of the methane seeps were obtained, which include their
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New sedimentological and coastal and marine geological data on the Quaternary marine deposits of the Ischia Island (Gulf of Naples, Southern Tyrrhenian Sea, Italy) Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-05-13 Gemma Aiello
Quaternary marine deposits of the Ischia Island have been analyzed based on marine geological survey and sedimentological data. The Ischia Island represents the emerged part of a large volcanic field, extending from the Procida island to the submerged volcanoes of the western Ischia offshore. The volcanic field develops over an area of about 42 km2, E-W trending, composed of calderas, such as the Ischia
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Applications and utility of the surface elevation table–marker horizon method for measuring wetland elevation and shallow soil subsidence-expansion Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-05-08 D.R. Cahoon; D.J. Reed; J.W. Day; J.C. Lynch; A. Swales; R.R. Lane
Byrnes et al. (Geo-Marine Letters 39:265–278, Byrnes et al. 2019) present subsidence data for Barataria Basin located south and west of New Orleans in coastal Louisiana to better inform wetland protection and restoration planning by the Louisiana Coastal Protection and Restoration Authority. They measured subsidence using geodetic GPS elevation surveys of rod benchmarks, similar to the rod benchmarks
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Geomorphometric comparison of submarine channel-levee complexes with fluvial river systems: observations from the Indus Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-04-21 R. Prerna; Kotha Mahender
An analogy between submarine channels and fluvial rivers has existed for long, especially on the basis of planform and morphometry. Underlying this broad resemblance are the minute disparities that shape and control these systems. In order to observe and quantify the variations between submarine channels and subaerial rivers, we present a first-ever geomorphometric investigation of one single system
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Enhanced erodibility of deep-sea sediments by presence of calcium carbonate particles Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-04-13 Jun Young Seo; Sun Min Choi; Ho Kyung Ha; Kyung Eun Lee
Using an erosion chamber, erodibility experiments on two different deep-sea sediments (mainly clayey silt) acquired in the western Pacific Ocean have been conducted to estimate the erosion rate and its potential controlling factors. Overall, the erosion rates of both deep-sea sediments were in the range of 10−7–10−5 kg m−2 s−1 which was two or three orders of magnitude lower than that of sediments
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Preservation of 34 S-enriched sulfides in fossil sulfate-methane transition zones: new evidence from Miocene outcrops of the northern Apennines (Italy) Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-03-26 C. Argentino; J. E. Johnson; S. Conti; C. Fioroni; D. Fontana
We provide new evidence of the preservation of 34S-enriched signals in methane seep-impacted sediments from two onshore Miocene outcrops located in the northern Apennines (Italy). Selected outcrops include methane-derived authigenic carbonates (MDAC) with δ13C composition between − 42.3 and − 18.2‰. MDACs contain chemosynthetic clams and abundant pyrite indicative of formation close to or within a
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Iron cycling in Arctic methane seeps Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-03-26 Wei-Li Hong; Pauline Latour; Simone Sauer; Arunima Sen; William P. Gilhooly; Aivo Lepland; Fotios Fouskas
Anoxic marine sediments contribute a significant amount of dissolved iron (Fe2+) to the ocean which is crucial for the global carbon cycle. Here, we investigate iron cycling in four Arctic cold seeps where sediments are anoxic and sulfidic due to the high rates of methane-fueled sulfate reduction. We estimated Fe2+ diffusive fluxes towards the oxic sediment layer to be in the range of 0.8 to 138.7 μmole/m2/day
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The step-by-step restriction of the Mediterranean (start, amplification, and consolidation phases) preceding the Messinian Salinity Crisis (climax phase) in the Bajo Segura basin Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-03-26 Hugo Corbí; Jesús M. Soria; Alice Giannetti; Alfonso Yébenes
This research explores the Messinian record in a western Mediterranean basin at the eastern end of the Betic Cordillera (the Garruchal section, southern sector of the Bajo Segura basin). Sedimentary facies development and foraminiferal assemblages were used as palaeoenvironmental proxies to characterize the palaeoceanographic evolution of the basin’s progressive restriction. Therefore, a succession
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Geological development of the Limpopo Shelf (southern Mozambique) during the last sealevel cycle Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-03-26 Stefan Wenau; Benedict Preu; Volkhard Spiess
Paleo-shorelines on continental shelves give insights into the complex development of coastlines during sealevel cycles. This study investigates the geologic development of the Limpopo Shelf during the last sealevel cycle using multichannel seismic and acoustic datasets acquired on the shelf in front of the Limpopo River mouth. A detailed investigation of seismic facies, shelf bathymetry, and a correlation
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A rock magnetic perspective of gas hydrate occurrences in a high-energy depositional system in the Krishna-Godavari basin, Bay of Bengal Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-03-19 Firoz Badesab; Pawan Dewangan; Virsen Gaikwad; Joju George Sebastian; M. Venkateshwarlu
We conducted a detailed rock magnetic study complemented by sedimentological and mineralogical methods on a 177.2-m-long sediment core of Hole NGHP-01-14A to constrain the influence of high-energy depositional environment on the magnetic mineral diagenesis and formation of gas hydrates in the Krishna-Godavari (K-G) basin, Bay of Bengal. Five sediment magnetic zones were identified based on the downcore
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Ice-rafted debris as a source of non-conservative behaviour for the εNd palaeotracer: insights from a simple model Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-03-18 Noam Vogt-Vincent; Jörg Lippold; Stefanie Kaboth-Bahr; Patrick Blaser
Neodymium isotopic composition (εNd) has enjoyed widespread use as a palaeotracer, principally because it behaves quasi-conservatively in the modern ocean. However, recent bottom water εNd reconstructions from the eastern North Atlantic are difficult to interpret under assumptions of conservative behaviour. The observation that this apparent departure from conservative behaviour increases with enhanced
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The use of Benthic Terrain Modeler (BTM) in the characterization of continental shelf habitats Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-02-22 Natacha de Oliveira, Alex Cardoso Bastos, Valéria da Silva Quaresma, Fernanda Vedoato Vieira
We applied a combined approach of benthic terrain modelling with sediment type distribution, using regional available data sets in order to map the distribution of seabed physical habitats along the Espírito Santo Continental Shelf, Brazil. The Benthic Terrain Modeler (BTM) was used to define benthic terrain classes, which were combined with ground truth data (sediment samples and seabed images) to
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The role of mass transport deposits contributing to fluid escape: Neogene outcrop and seismic examples from north Taranaki, New Zealand Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-02-18 G. H. Browne; S. Bull; M. J. Arnot; A. F. Boyes; P. R. King; K. Helle
Many sedimentary structures are the manifestation of fluid escape in sedimentary basins. This paper examines outcrop and seismic examples in upper Miocene deep-water sandstones and siltstones of north Taranaki, New Zealand. In outcrop examples of fluid escape features comprise discordant bodies within otherwise uniformly bedded surrounding stratigraphy, features characterized by steep sided, over-hanging
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Sidescan sonar meets airborne and satellite remote sensing: challenges of a multi-device seafloor classification in extreme shallow water intertidal environments Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-02-12 R. M. Capperucci; A. Kubicki; P. Holler; A. Bartholomä
Tidal ecosystems like the Wadden Sea are particularly valuable for their ecological and economic importance. Here, the natural dynamics of the abiotic and biotic processes is threatened by the human pressure, and great efforts are made on mapping and monitoring programs. Remote sensing techniques (e.g., satellite and airborne sources) are commonly used on land and intertidal areas, whereas hydroacoustic
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Spectral differences in the underwater light regime caused by sediment types in New Zealand estuaries: implications for seagrass photosynthesis Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-02-11 Mariana Coppede Cussioli; Dorothea Seeger; Daniel R. Pratt; Karin R. Bryan; Kai Bischof; Willem P. de Lange; Janet F. Bornman; Conrad A. Pilditch
The underwater light regime is fundamental to the ecological health of aquatic systems because it is a limiting factor for photosynthesis in marine plants such as seagrasses. Although seagrass meadows are a key component of coastal systems, their survival has been threatened by increased turbidity levels, both from resuspension of marine sediments and input of terrestrial material. The objective of
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Structural-morphological and sedimentary features of forearc slope off Miyagi, NE Japan: implications for development of forearc basins and plumbing systems Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-27 Jih-Hsin Chang; Jin-Oh Park; Tzu-Ting Chen; Asuka Yamaguchi; Tetsuro Tsuru; Yuji Sano; Ho-Han Hsu; Kotaro Shirai; Takanori Kagoshima; Kentaro Tanaka; Chiori Tamura
Multibeam (MB) and subbottom profile (SBP) data along the forearc slope off Miyagi, Japan, are combined to investigate structural-morphological and sedimentary structures along the forearc slope of the Japan Trench subduction zone. In addition to dip-oriented slope gullies, the MB data image a nearly dip-perpendicular slope trough bounded by a fault scarp landward of the trench-slope break. Seaward
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Accuracy of sand beach topography surveying by drones and photogrammetry Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-23 Elisa Casella; Jan Drechsel; Christian Winter; Markus Benninghoff; Alessio Rovere
Beaches are characterized by high morphodynamic activity, and high-frequency measurements are needed to understand their states and rates of change. Ideally, beach survey methods should be at once accurate, rapid and low-cost. Recently, unmanned aerial systems (drones) have been increasingly utilized to measure beach topography. In this paper, we present a review of the state of art in drones and photogrammetry
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Genesis and evolution of the South Atlantic volcanic islands offshore Brazil Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-16 Webster Mohriak
The Brazilian continental margin includes several volcanic islands, submerged volcanic seamounts, and a unique non-volcanic archipelago located in a transform segment of the Equatorial South Atlantic. The mechanism of formation of these islands is related to post-breakup magmatic episodes dated as Late Cretaceous to Pleistocene. Diverse Late Cretaceous to Paleogene alkaline magmatic episodes are registered
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Sedimentary records of nitrogen isotope in the western tropical Pacific linked to the eastern tropical Pacific denitrification during the last deglacial time Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-16 Xiaowei Zhu; Guodong Jia; Weihai Xu; Xufeng Zheng; Jianguo Liu; Yuhang Tian; Li Miao; Wen Yan
The influence of past variations in water column denitrification (WCD) in the eastern tropical Pacific (ETP) on the western tropical Pacific (WTP) remains ambiguous, due to the deficiency of enough down-core records of nitrogen isotope (δ15N) in the WTP. In this study, sedimentary δ15N record down a core from the northern WTP is investigated to revisit this issue. After elucidating the potential presence
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The role of cuspate spits on wave attenuation and energy redistribution in a coastal lagoon, Lagoa dos Patos, Brazil Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-11 Inaiê Malheiros Miranda, Elírio Ernestino Toldo, Antonio Henrique da Fontoura Klein, Darrell Strauss, Guilherme Vieira da Silva
This research uses a process-based model (Delft3D), validated with measured wave data, to investigate the controls that a cuspate shoreline and its associated submerged morphology have on wave generation, propagation, and attenuation within a large elongated lagoon (Lagoa dos Patos, Brazil). A method based on the Energy-Flux-Method was applied to the historical wind dataset to define representative
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Inverse response of 231 Pa/ 230 Th to variations of the Atlantic meridional overturning circulation in the North Atlantic intermediate water Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-07 Finn Süfke; Hartmut Schulz; Jeemijn Scheen; Sönke Szidat; Marcel Regelous; Patrick Blaser; Frerk Pöppelmeier; Tyler J. Goepfert; Thomas F. Stocker; Jörg Lippold
This study aims to provide a more detailed understanding of the behavior of 231Pa/230Th under varying ocean circulation regimes. The North Atlantic provides a unique sedimentary setting with its ice-rafted detritus (IRD) layers deposited during glacial times. These layers have been found north of 40° N (Ruddiman Belt) and are most pronounced during Heinrich Stadials. Most of these sediments have been
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Foraminiferal δ 18 O reveals gas hydrate dissociation in Arctic and North Atlantic ocean sediments Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-07 Pierre-Antoine Dessandier; Chiara Borrelli; Haoyi Yao; Simone Sauer; Wei-Li Hong; Giuliana Panieri
Paleoceanographic investigations in the Arctic and north Atlantic are crucial to understanding past and current climate change, in particular considering amounts of pressure-temperature sensitive gas stored in marine sediments of the region. Many paleoceanographic studies are based on foraminiferal oxygen and carbon stable isotope compositions (δ18O, δ13C) from either planktonic specimens, benthic
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Use of 210 Pb and 137 Cs in the assessment of recent sedimentation in Patos Lagoon, southern Brazil Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-04 Michel Doeppre Ivanoff, Elírio Ernestino Toldo, Rubens Cesar Lopes Figueira, Paulo Alves de Lima Ferreira
In this study, the sedimentation conditions of Lagoa dos Patos, southern Brazil, were analyzed by applying 210Pb and 137Cs geochronological methods on four geological cores. The sedimentation rates showed a decreasing north-to-south pattern, indicating a strong influence of the Guaíba River discharge (the main Patos Lagoon tributary) on the transport of sediments into the interior of the lagoon. Core
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Mud deposits at Cassino beach: role of dredging Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-03 Lauro Júlio Calliari, Arthur Antônio Machado, Patricia Marroig, Susana Vinzon, Norton Gianuca
Mud deposits on Cassino beach are associated with waves generated from storms during cold front passages and extratropical cyclones from the southern quadrant. During such episodes fluid mud deposited at the shoreface and surf zone is transported towards the surf zone and the sandy beach prism. The first mention on the origin of mud has always attributed a source exclusively natural for the deposits
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South Brazilian Bight mid- to late Holocene hydrographic fluctuations Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-03 Renata H. Nagai, Cristiano M. Chiessi, Henning Kuhnert, Silvia H. M. Sousa, Ilana E. K. C. Wainer, Rubens C. L. Figueira, Michel M. Mahiques
Here, we present two high temporal resolution Holocene sea surface temperature (SST) and salinity (SSS) reconstructions for the SW Atlantic. Mg/Ca data together with the oxygen isotopic composition (δ18O) of a shallow dwelling planktonic foraminifera species (Globigerinoides ruber (pink)). Two marine sediment cores collected at ~ 25°S are used to assess mid- to late Holocene sea surface hydrographic
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Spatial and temporal variability of free gas content in shallow sediments: Lake Kinneret as a case study Geo-Mar. Lett. (IF 1.429) Pub Date : 2020-01-03 E. Uzhansky; B. Katsnelson; A. Lunkov; I. Ostrovsky
Organic-rich aquatic sediments are a significant source of methane to the atmosphere. In situ remote quantifications of gas content in shallow sediment is a complex task due to its large spatiotemporal heterogeneity. The spatial and multiannual changes of free gas (methane) content (Θ) in shallow sediments were studied in deep subtropical Lake Kinneret. We implemented recently developed acoustic methodology
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Hydrocarbon gases in seafloor sediments of the TATAR strait, the northern sea of Japan Geo-Mar. Lett. (IF 1.429) Pub Date : 2019-12-14 Andrey Yatsuk; Renat Shakirov; Alexander Gresov; Anatoly Obzhirov
The distributions of hydrocarbon gases (HCGs) from C1-C5 in seafloor sediments of the South Tatar sedimentary basin (northern Sea of Japan) were obtained during five research cruises from 2012 to 2017. As a result of this work, areas of gas hydrates, gas flares, and anomalous gas concentrations were discovered. The concentration of HCGs in seafloor sediment, as determined by the “headspace method”
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Crab burrow aspect ratio influences particle capture rates on intertidal sandflats Geo-Mar. Lett. (IF 1.429) Pub Date : 2019-12-11 Marine Le Minor; Julia C. Mullarney; Conrad A. Pilditch; Katrin Huhn
Crabs are ecosystem engineers that dig burrows, which can trap sediment. We used a field experiment to explore how burrow aspect ratio (depth/diameter) affects the trapping efficiency of sediments and organic material. Arrays of burrows mimics were constructed using tubes of similar depths but two different opening diameters: fat tubes (aspect ratio of 3.8) and thin tubes (7.1). Different arrays were
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Geohabitats characterization in areas of dredge sediment disposals on Rio de Janeiro continental shelf, adjacent to Guanabara Bay: Brazil Geo-Mar. Lett. (IF 1.429) Pub Date : 2019-12-10 Caroline Fontelles Ternes, Gilberto Tavares de Macedo Dias, Marcelo Sperle Dias
Disposal of dredged sediments from harbor areas is often carried out without prior characterization and diagnosis of the benthic ecosystem and its relationships with the physical environment. Geohabitats studies contribute to this previous characterization, showing how geological and geomorphological features are associated with the benthic ecosystems of a given location. To investigate these relationships
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